thanks for joining us. captioning sponsored by macneil/lehrer productions >> ifill: in the nine weeks since the schoolhouse shootings in newtown, connecticut, police around the country report hundreds more have been victims of gun violence. good evening. i'm gwen ifill. >> woodruff: and i'm judy woodruff. tonight begins a weeklong focus on guns here on pbs, "after newtown." on the newshour this evening, we look at political and other developments since the december tragedy and zero in on the gun debate in colorado. >> in the divisive atmosphere of the gun debate, both sides, at the federal and state level, say they know the coming months won't be easy. but they will be critical. >> ifill: then, we take up the arguments for and against the proposed construction of the keystone pipeline, as environmental activists mounted a protest this weekend. >> woodurff: ray suarez updates the hugo chavez story, after the president's surprise return to venezuela following more than two months of cancer treatment in cuba.